Multi-speed transmission

ABSTRACT

A transmission has an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes. The torque transmitting devices are each selectively engageable in combinations of at least two to establish at least ten forward speed ratios and at least one reverse speed ratio.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices, and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches or brakes, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In an aspect of the present invention a transmission is provided havingan input member, an output member, a first, second, third and fourthplanetary gear sets each having sun gears, carrier members and ringgears. The input member is continuously interconnected with the sun gearof the first planetary gear set. The output member is selectivelyinterconnected with the ring gear of the fourth planetary gear set.

Additionally, a first interconnecting member continuously interconnectsthe sun gear member of the ring gear of the first planetary gear setwith the carrier member of the second planetary gear set and the sungear of the third planetary gear set, a second interconnecting membercontinuously interconnects the carrier member of the first planetarygear set with the sun gear of the second planetary gear set and the sungear of the fourth planetary gear set and a third interconnecting membercontinuously interconnects the carrier member of the third planetarygear set with the carrier member of the fourth planetary gear set.

Further, a first torque transmitting device is selectively engageable tointerconnect the sun gear of the first planetary gear set and the inputmember with the carrier member of the fourth planetary gear set, asecond torque transmitting device is selectively engageable tointerconnect the ring gear of the second planetary gear set with thecarrier member of the third planetary gear set, a third torquetransmitting device is selectively engageable to interconnect the ringgear of the second planetary gear set with the stationary member, afourth torque transmitting device is selectively engageable tointerconnect the ring gear of the first planetary gear set with thestationary member, a fifth torque transmitting device is selectivelyengageable to interconnect the ring gear member of the third planetarygear set with the stationary member, and a sixth torque transmittingdevice is selectively engageable to interconnect the carrier member ofthe first planetary gear set with the stationary member. The torquetransmitting devices are selectively engageable in combinations of atleast two to establish at least ten forward speed ratios and at leastone reverse speed ratio between the input member and the output member.

It is thus an aspect of the present invention to provide a transmissionhaving four planetary gear sets.

It is a further aspect of the present invention to provide atransmission having ten forward speeds and at least one reverse.

It is a still further aspect of the present invention to provide atransmission having four planetary gear sets, a plurality of couplingmembers and a plurality of torque transmitting devices.

Further features, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that in the particular exampleprovided, the ten speed automatic transmission of the present inventionhas an arrangement of permanent mechanical connections between theelements of the four planetary gear sets. A first component or elementof a first planetary gear set is permanently coupled to a firstcomponent or element of a second planetary gear set. A second componentor element of the first planetary gear set is permanently coupled to asecond component or element of a second planetary gear set. A firstcomponent or element of a second planetary gear set is permanentlycoupled to a first component or element of a fourth planetary gear set.A second component or element of a second planetary gear set ispermanently coupled to a first component or element of a third planetarygear set. Finally, a second component or element of the third planetarygear set is permanently coupled to a second component or element of afourth planetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear set are each represented by a node. Therefore, a single levercontains three nodes: one for the sun gear, one for the planet gearcarrier, and one for the ring gear. The relative length between thenodes of each lever can be used to represent the ring-to-sun ratio ofeach respective gear set. These lever ratios, in turn, are used to varythe gear ratios of the transmission in order to achieve appropriateratios and ratio progression. Mechanical couplings or interconnectionsbetween the nodes of the various planetary gear sets are illustrated bythin, horizontal lines and torque transmitting devices such as clutchesand brakes are presented as interleaved fingers. If the device is abrake, one set of the fingers is grounded. Further explanation of theformat, purpose and use of lever diagrams can be found in SAE Paper810102, “The Lever Analogy: A New Tool in Transmission Analysis” byBenford and Leising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the third node 14C of the firstplanetary gear set 14. The first node 14A of the first planetary gearset 14 is coupled to a first node 16A of the second planetary gear set16 and to the first node 20A of the fourth planetary gear set 20. Thesecond node 14B of the first planetary gear set 14 is coupled to secondnode 16B of the second planetary gear set 16 and to the first node 18Aof the third planetary gear set 18. The second node 18B of the thirdplanetary gear set 18 is coupled to the second node 20B of the fourthplanetary gear set 20.

A first clutch 26 selectively connects the third node 14C of the firstplanetary gear set 14 with the second node 18B of the third planetarygear set. A second clutch 28 selectively connects the third node 16C ofthe second planetary gear set 16 with the second node 18B of the thirdplanetary gear set 18. A first brake 30 selectively connects the thirdnode 16C of the second planetary gear set 16 with a stationary elementor a transmission housing 50. A second brake 32 selectively connects thefirst node 18A of the third planetary gear set 18 with the stationaryelement or a transmission housing 50. A third brake 34 selectivelyconnects the third node 18C of the third planetary gear set 18 with thestationary element or a transmission housing 50. A fourth brake 36selectively connects the first node 20A of the fourth planetary gear set20 with the stationary element or the transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches, brakes, and couplings are correspondinglypresented whereas the nodes of the planetary gear sets now appear ascomponents of planetary gear sets such as sun gears, ring gears, planetgears and planet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14C, aring gear member 14B and a planet gear carrier member 14A that rotatablysupports a first set of planet gears 14D (only one of which is shown)and a second set of planet gears 14E (only one of which is shown). Thefirst set of planet gears 14D are each configured to intermesh with boththe sun gear member 14C and the second set of planet gears 14E. Thesecond set of planet gears 14E are each configured to intermesh withboth the ring gear member 14B and the first set of planet gears 14D. Thesun gear member 14C is connected for common rotation with a first shaftor interconnecting member 42 and with input shaft or member 12. The ringgear member 14B is connected for common rotation with a second shaft orinterconnecting member 44. The planet carrier member 14A is connectedfor common rotation with a third shaft or interconnecting member 46 andwith a fourth shaft or interconnecting member 48.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The planet gears16D are each configured to intermesh with both the sun gear member 16Aand the ring gear member 16C. The sun gear member 16A is connected forcommon rotation with the fourth shaft or interconnecting member 48 andwith a fifth shaft or interconnecting member 52. The ring gear member16C is connected for common rotation with a sixth shaft orinterconnecting member 54. The planet carrier member 16B is connectedfor common rotation with the second shaft or interconnecting member 44and with a seventh shaft or interconnecting member 56.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18C and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The set ofplanet gears 18D are each configured to intermesh with both the sun gearmember 18A and the ring gear member 18C. The sun gear member 18A isconnected for common rotation with the seventh shaft or interconnectingmember 56. The ring gear member 18C is connected for common rotationwith an eighth shaft or interconnecting member 58. The planet carriermember 18B is connected for common rotation with a ninth shaft orinterconnecting member 60 and with a tenth shaft or interconnectingmember 62.

The planetary gear set 20 includes a sun gear member 20A, a ring gearmember 20C and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The set ofplanet gears 20D are each configured to intermesh with both the sun gearmember 20A and the ring gear member 20C. The sun gear member 20A isconnected for common rotation with the fifth shaft or interconnectingmember 52. The ring gear member 20C is connected for common rotationwith the output shaft or member 22. The planet carrier member 20B isconnected for common rotation with the tenth shaft or interconnectingmember 62 and with an eleventh shaft or interconnecting member 64.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or the clutches 26, 28 and the brakes30, 32, 34 and 36 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the first shaft or interconnecting member 42 and the input shaftor member 12 with the tenth shaft or interconnecting member 64. Thesecond clutch 28 is selectively engageable to connect the sixth shaft orinterconnecting member 54 with the ring gear member 60. The first brake30 is selectively engageable to connect the sixth shaft orinterconnecting member 54 with the stationary element or thetransmission housing 50 in order to prevent the sixth shaft orinterconnecting member 54 from rotating relative to the transmissionhousing 50. The second brake 32 is selectively engageable to connect thesecond shaft or interconnecting member 44 with a stationary element orthe transmission housing 50 in order to prevent the second shaft orinterconnecting member 44 from rotating relative to the transmissionhousing 50. The third brake 34 is selectively engageable to connect theeighth shaft or interconnecting member 58 with the stationary element orthe transmission housing 50 in order to prevent the eighth shaft orinterconnecting member 58 from rotating relative to the transmissionhousing 50. The fourth brake 36 is selectively engageable to connect thethird shaft or interconnecting member 46 with the stationary element orthe transmission housing 50 in order to prevent the third shaft orinterconnecting member 46 from rotating relative to the transmissionhousing 50.

Referring now to FIGS. 2 and 3, the operation of the embodiment of theten speed transmission 10 will be described. It will be appreciated thatthe transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with a triple overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,first brake 30, second brake 32, third brake 34 and fourth brake 36), aswill be explained below. FIG. 3 is a truth table presenting the variouscombinations of torque-transmitting elements that are activated orengaged to achieve the various gear states. Actual numerical gear ratiosof the various gear states are also presented although it should beappreciated that these numerical values are exemplary only and that theymay be adjusted over significant ranges to accommodate variousapplications and operational criteria of the transmission 10. An exampleof the gear ratios that may be obtained using the embodiments of thepresent invention are also shown in FIG. 3. Of course, other gear ratiosare achievable depending on the gear diameter, gear teeth count and gearconfiguration selected.

To establish reverse gear, the first clutch 26 and the third brake 34are engaged or activated. The first clutch 26 connects the first shaftor interconnecting member 42 and the input shaft or member 12 with thetenth shaft or interconnecting member 64. The third brake 34 connectsthe eighth shaft or interconnecting member 58 with the stationaryelement or the transmission housing 50 in order to prevent the eighthshaft or interconnecting member 58 from rotating relative to thetransmission housing 50. Likewise, the ten forward ratios are achievedthrough different combinations of clutch and brake engagement, as shownin FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches and brakes not specifically referenced in a given gearstate are inactive or disengaged and, second of all, that during gearshifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

What is claimed is:
 1. A transmission comprising: an input member; anoutput member; first, second, third and fourth planetary gear sets eachhaving first, second and third members, wherein the input member iscontinuously interconnected with the third member of the first planetarygear set and output member is continuously interconnected with the thirdmember of the fourth planetary gear set; a first interconnecting membercontinuously interconnecting the second member of the first planetarygear set with the second member of the second planetary gear set and thefirst member of the third planetary gear set; a second interconnectingmember continuously interconnecting the first member of the firstplanetary gear set with the first member of the second planetary gearset and the first member of the fourth planetary gear set; a thirdinterconnecting member continuously interconnecting the second member ofthe third planetary gear set with the second member of the fourthplanetary gear set; and six torque transmitting devices each selectivelyengageable to interconnect at least one of the first, second, and thirdmembers with at least one other of the first members, second members,third members and a stationary member, and wherein the torquetransmitting devices are selectively engageable in combinations of atleast two to establish at least ten forward speed ratios and at leastone reverse speed ratio between the input member and the output member.2. The transmission of claim 1 wherein a first of the six torquetransmitting devices is selectively engageable to interconnect the thirdmember of the first planetary gear set and the input member with thesecond member of the fourth planetary gear set.
 3. The transmission ofclaim 2 wherein a second of the six torque transmitting devices isselectively engageable to interconnect the third member of the secondplanetary gear set with the second member of the third planetary gearset.
 4. The transmission of claim 3 wherein a third of the six torquetransmitting devices is selectively engageable to interconnect the thirdmember of the second planetary gear set with the stationary member. 5.The transmission of claim 4 wherein a fourth of the six torquetransmitting devices is selectively engageable to interconnect thesecond member of the first planetary gear set with the stationarymember.
 6. The transmission of claim 5 wherein a fifth of the six torquetransmitting devices is selectively engageable to interconnect the thirdmember of the third planetary gear set with the stationary member. 7.The transmission of claim 6 wherein a sixth of the six torquetransmitting devices is selectively engageable to interconnect the firstmember of the first planetary gear set with the stationary member. 8.The transmission of claim 1 wherein the third member of the firstplanetary gear set, the first member of the second planetary gear set,the first member of the third planetary gear set and the first member ofthe fourth planetary gear set are sun gears, the first member of thefirst planetary gear set, the second member of the second planetary gearset, the second member of the third planetary gear set and the secondmember of the fourth planetary gear set are carrier members and thesecond member of the first planetary gear set, third member of thesecond planetary gear set, the third member of the third planetary gearset and the third member of the fourth planetary gear set are ringgears.
 9. The transmission of claim 1 wherein four of the six torquetransmitting devices are brakes and two of the six torque transmittingdevices are clutches.
 10. The transmission of claim 1 wherein thestationary member is a transmission housing.
 11. A transmissioncomprising: an input member; an output member; first, second, third andfourth planetary gear sets each having first, second and third members,wherein the input member is continuously interconnected with the thirdmember of the first planetary gear set and output member is continuouslyinterconnected with the third member of the fourth planetary gear set; afirst interconnecting member continuously interconnecting the secondmember of the first planetary gear set with the second member of thesecond planetary gear set and the first member of the third planetarygear set; a second interconnecting member continuously interconnectingthe first member of the first planetary gear set with the first memberof the second planetary gear set and the first member of the fourthplanetary gear set; a third interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe second member of the fourth planetary gear set; a first torquetransmitting device selectively engageable to interconnect the thirdmember of the first planetary gear set and the input member with thesecond member of the fourth planetary gear set; a second torquetransmitting device selectively engageable to interconnect the thirdmember of the second planetary gear set with the second member of thethird planetary gear set; a third torque transmitting device selectivelyengageable to interconnect the third member of the second planetary gearset with the stationary member; a fourth torque transmitting deviceselectively engageable to interconnect the second member of the firstplanetary gear set with the stationary member; a fifth torquetransmitting device selectively engageable to interconnect the thirdmember of the third planetary gear set with the stationary member; and asixth torque transmitting device selectively engageable to interconnectthe first member of the first planetary gear set with the stationarymember, and wherein the torque transmitting devices are selectivelyengageable in combinations of at least two to establish at least tenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 12. The transmission of claim 11wherein the third member of the first planetary gear set, the firstmember of the second planetary gear set, the first member of the thirdplanetary gear set and the first member of the fourth planetary gear setare sun gears, the first member of the first planetary gear set, thesecond member of the second planetary gear set, the second member of thethird planetary gear set and the second member of the fourth planetarygear set are carrier members and the second member of the firstplanetary gear set, third member of the second planetary gear set, thethird member of the third planetary gear set and the third member of thefourth planetary gear set are ring gears.
 13. The transmission of claim11 wherein the stationary member is a transmission housing.
 14. Atransmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members, wherein the input member is continuouslyinterconnected with the sun gear of the first planetary gear set andoutput member is continuously interconnected with the ring gear of thefourth planetary gear set; a first interconnecting member continuouslyinterconnecting the ring gear of the first planetary gear set with thecarrier member of the second planetary gear set and the sun gear of thethird planetary gear set; a second interconnecting member continuouslyinterconnecting the carrier member of the first planetary gear set withthe sun gear of the second planetary gear set and the sun gear of thefourth planetary gear set; a third interconnecting member continuouslyinterconnecting the carrier member of the third planetary gear set withthe carrier member of the fourth planetary gear set; a first torquetransmitting device selectively engageable to interconnect the sun gearof the first planetary gear set and the input member with the carriermember of the fourth and third planetary gear set; a second torquetransmitting device selectively engageable to interconnect the ring gearof the second planetary gear set with the carrier member of the thirdplanetary gear set; a third torque transmitting device selectivelyengageable to interconnect the ring gear of the second planetary gearset with the stationary member; a fourth torque transmitting deviceselectively engageable to interconnect the ring gear of the firstplanetary gear set with the stationary member; a fifth torquetransmitting device selectively engageable to interconnect the ring gearmember of the third planetary gear set with the stationary member; and asixth torque transmitting device selectively engageable to interconnectthe carrier member of the first planetary gear set with the stationarymember, and wherein the torque transmitting devices are selectivelyengageable in combinations of at least two to establish at least tenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 15. The transmission of claim 14wherein the stationary member is a transmission housing.